The invention relates to foldable ladders of the type which are folded for storage in the event of an emergency at which time they can be unfolded and used to escape from an elevated structure. These ladders are often used as emergency fire escape means and may be secured in a container outside a window, for immediate use. Similar, though shorter ladders, are often used in boats to permit ease of returning into the boat from, for example, the water.
Foldable ladders are well known and have been in use for many years. An extremely old and very common type of foldable ladder is a so-called rope ladder. These usually comprise a series of elongated rigid steps maintained approximately parallel to each other by two ropes, one secured to each end of the steps. The rope permits rolling the ladders into a cylindrical bundle.
The main disadvantage of the known foldable ladders resides in their lack of apparent stability. As these ladders may find utilization as emergency exits, persons not used to climbing ladders may find themselves in a position when they must use a folding ladder in an emergency. If the ladder feels insecure, one often encounters difficulty in using a ladder for the first time. If the person is at all acrophobic, the use of prior art type foldable ladders can be devastating, if not fatal.
In an endeavor to avoid the deficiencies of the prior art type ladders, the instant invention teaches a ladder which, when in use, provides a relatively rigid structure, while still permitting the ladder to be folded or collapsed into a small space.